This invention relates to seat cushions which may be selectively deformed to the shape of the user and more particularly to a seat cushion which may be deformed selectively to permit evacuation of the air therein upon forcible compression of the seat and selectively to permit re-entry of the air upon release of the compression force or to prevent the re-entry of the air to maintain the deformed shape.
It is known to provide a seat with a resilient foam cushion encased within a covering. When one sits on such a seat the foam cushioning compresses as air is expelled from the cells of the foam. The air either exits through the cover itself or leaks out of the cover since the covers are porous and in any event are not airtight. Thereafter when the compression is released from the seat by the person getting off, the seat reforms by air re-entering the cells of the foam until the foam looses its resiliency and is no longer effectively compressible, i.e., no longer holds it original uncompressed shape. When such a foam is applied to the rigid base of a seat, such as the seat of a motorcycle, the cushioning effect is minimal after the user has been seated on the seat for some time. The same is true in regard to other seats including those in automobiles, wheel chairs, stadium cushions, office chairs and the like. The air is evacuated and the rigid base beneath it provides the support. Most of such seats, such as the concrete or wooden seats in a sports stadium or arena, are very hard, and thus the cushion placed thereon does not provide must comfort to a seated person. Additionally, there is no adjustability and the pressure points of the body of the seated person on the seat remains stationary and may result in a sore or numb buttocks. One reason for this is that the soft tissues of the buttocks spread and the pelvis or bony prominences settle. Enjoyment of a sports event may be sacrificed due to the loss of comfort resulting from inadequate cushioning.
In our aforesaid U.S. application Ser. No. 08/615,615, now U.S. Pat. No. 5,711,573, a motorcycle seat having a deformable seat cushion is disclosed which comprises a plastic foam material encased within an air tight skin and a valve member located externally of the seat and communicating in sealed relationship through the skin into the foam so that when the valve is open and a compression force is applied to the foam, such as by a person sitting on the seat, air is evacuated and the seat conforms to the shape of the user's buttocks. When the valve is opened and the person disembarks from the seat, air re-enters the cells of the foam to reshape the seat to its original shape.
It was subsequently recognized that when the foam is compressed to a shape and is maintained in the compressed shape over a relatively long period of time, the foam loses its "memory," that is, it loses its ability to return to its initial state, and eventually will not return to its original uncompressed configuration. To some extent, this defeats the adjustability feature of the selectively deformable seat. Thus in our co-pending U.S. application Ser. No. 08,869,373, we disclosed a motorcycle seat having a foam cushion which permits air to be evacuated from and returned into the cells of the foam selectively and additionally provides a means for automatically permitting air to re-enter the seat after the rider has disembarked from the seat.
In that application the disclosure related to a seat for a motorcycle having a first valve permitting air to be evacuated from and returned to the interior of the seat selectively to vary the pressure points on the body of the cyclist and a second valve permitting air to enter into the interior of the seat when the first valve is closed and no one is on the seat, but which prevents air from exhausting from the interior of the seat.
In order to utilize the concepts of our aforesaid patent and patent application to mobile stadium seat cushions a number of modifications have been found necessary. For example, stadium seats are notoriously narrow, e.g., in the order of approximately 14 inches and spectators are closely spaced. Thus, it is impracticable to place the valve actuating structure on the side as in the motorcycle seat. Additionally, since certain stadium seats are concrete, and since the cushion cannot be too huge or heavy, since it is intended to be carried to and from the stadium, variations in the cushions had to be considered for use under these circumstances.